Thank you link, that clears up a whole lot to me - it bugged me like crazy, couldn't figure why it happens! Also, I am sad if this is the case cause it is one of the greatest games out there. I play with european players Animal Crossing City Folk and Mk basically every day, I hope I will find european Brawl players as well.
About the router problem, I remembered when I was searching for the possible lag fixes the other day, I came across a 3-part tutorial on how to force the router to dedicate a host to Wii, it can be seen here:
Anyways, try to login to your router by entering
http://192.168.1.1/ or something similar to your browser (this address depends on the router model). From there you can learn and change your connection settings, and use them for the Wii Internet settings. I think you can create 3 different connection settings in the Wii, so you can play around with settings in each one of them until you find which one works the best.